is 2 42157 - 1
has 12691 decimal digits
takes 0.000 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
-unknown- primality tests remaining
ResidueStatus
L-L-unknown--unknown-
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actualunknown10000000020000000000.210746.8987%0.210746.8987%46.8987%
PrimeNet2400.000060.0000%500100000.00004.4720%0.000061.7888%1.7888%
GPU722440.000163.6364%500100000.00001.9420%0.000164.3426%0.7062%
Difference-44-0.0001-63.6364%+99999500+1999990000+0.2107+44.9567%+0.2106-17.4439%-17.4439%

Known prime factors (2 factors, 158.5 bits, 0.37606450% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
4215723285768988002411651.04827617915160
23 × 32 × 5 × 11 × 23 × 353 × 859
2014-04-233538590.01223.939e-77.437e-7
4215722774890478468704939609660548179933107.4892701199145867673807387819407
3 × 900399715289224602462606469
2021-11-0639003997152892246024626064693.529e+125.078e+169.484e+16

1 Composite Factors:
exponentprime factorscomposite factordigitsbits*
4215753033083840867793869733815599691905454686231355948158.538
P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2016-09-19T05:18:19kkmrkkblmbrbkManual testing100000000200000000012-
skipped known factor: 2328576898800241
--0.211--39.180%


Trial Factoring results:
No TF results for M42157


ECM factoring results:

Old Calculation Method

Total ECM effort:23.548 GHz-days
Estimated T-Level:34.537
DigitsB1CurvesCompleteFacMiss
20110002287 / 10022.8700.000%
25500002287 / 2808.1680.028%
302500002004 / 6403.1314.356%
3510000001421 / 15660.90740.345%

New Calculation Method

Total ECM effort:23.548 GHz-days
Estimated T-Level:34.537
DigitsB1CompleteFacMiss
2011000300.7180.000%
255000056.5850.000%
302500008.2950.025%
3510000000.99237.089%
4030000000.09890.630%
45110000000.00899.181%


ECM Summary

B1B2factorcurvesGHz-days
5000050000002830.211
250000250000005832.171
10000001000000001,25618.71
10000001000000001652.458


Lucas-Lehmer results:
No L-L results for M42157


PRP results:
dateuseridcompidcofactorsres64PRP
2017-09-21T19:53:21Oliver KruseDoppelherz
2328576898800241
CFD5529F794E2B__no
2017-09-21T21:39:02Oliver KruseManual testing
2328576898800241
CFD5529F794E2B__no
2017-09-21T22:13:04Oliver KruseManual testing
2328576898800241
CFD5529F794E2B__no
2017-11-06T04:32:39kkmrkkblmbrbkc4.xlarge
2328576898800241
CFD5529F794E2B__no
2020-04-17T13:49:14Oliver KruseManual testing
2328576898800241
08E426E8442EDC__no
2021-11-06T17:30:59mikrNitron
2328576898800241
227748904784687049396096605481799
08E426E8442EDC6Eno
2021-11-06T18:41:51SRJ2877LTOS
2328576898800241
227748904784687049396096605481799
08E426E8442EDC6Eno


P-1 factor-bounds graph:
B1 = 100000000, B2 = 2000000000 (P-1 stage 2)
B1 = 100000000 (P-1 stage 1)
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TF factor-bounds graph:
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Last modified: 2022-05-08T10:21:51+00:00